A few issues to consider:
1) Make sure that there is no easement/right of way on your courtyard and that the entire courtyard is in fact your lot. This can be found by looking at the special by-laws (if any) or on the plan entitlements when you purchased the unit.
2) The OC must pay for the damage to your property (tiles and pots). I would send them the bill.
3) If it were me, I would be taking the matter to the tribunal, however, in the interim if there is no other-wise 'noted' entitlement to access your property then call the police as what you have described sounds like trespassing.